P2503 code after replace alternator
 

hi everybody :)
its my first post, and i have a problem after replace alternator. I replace because is not chargiging when i start engine only and all device like AirCon, light , etc was off, so to make charge battery i need run something for example light or aircon. But i dont have this code anyway. Yesterday i replace for working one, same type, now work OK, 13.9-14.4V but i have this code :( i dont know where i can find problem , the description of this coder said "low charging voltage" but i think its fine...

Any body can help please ?

Thanks

The system is a smart charge system, It only charges when the ecu detects load on the electrics like lights/aircon. theres nothing wrong with it. Its designed like that. I'd bet the alternator you have isn't a genuine one or a smart charge one at that

I so suprise, problem is if i dont use any device like light or aircon for example in day time, my battery flat so fast, i driving in day time last week and in 5 day i not use light or aircon so after 5 days my battery was totaly flat... somebody said the charging system should charging all time when engine start, to keep battery fully charged, so now i dont know...

if your sure the battery is good Id find out what is draining the system, a amp meter inline with a main battery lead will help,
with the meter inline see how many amps are being drawn with the ignition off, do you have a amp or something like that ?

i check tomorow, battery is fine, and i think lsast time battery draining because i use my car every day i use car audio, GPS, charge my phone, and i not use light or aircon, that whay my battery get flat after 5 days... i think, but i check tomorow amp when engine off.

Conventional charging systems work like that however a Subaru doesn't. it needs load to charge, sidelights usually do the trick